删除扩展属性在发生定期约会时使用时引发错误

Question

我正在开发一个应用程序，将一个交换日历同步到另一个日历。我在交换约会上放置了扩展属性，以保留两个日历中约会之间的映射。 一切正常，直到我尝试从定期约会中删除扩展属性。 当我尝试这样做时，我收到错误：

The delete action is not supported for this property.

下面是演示错误的代码片段：

public void ExchangeTest()
{
    ExchangeService service = new ExchangeService(ExchangeVersion.Exchange2007_SP1)
    {
        Credentials = new NetworkCredential("username", "password", "domain")
    };
    service.AutodiscoverUrl("[e-mail]");
    Appointment appt = new Appointment(service)
    {
        Recurrence = new Recurrence.DailyPattern(DateTime.Now, 2) { NumberOfOccurrences = 3},
        Start = DateTime.Now,
        End = DateTime.Now.AddHours(2),
        Subject = "Test Appointment"
    };
    NameResolutionCollection resolutionCollection = service.ResolveName("username", ResolveNameSearchLocation.DirectoryOnly, false);
    string mailboxAddress = resolutionCollection.First().Mailbox.Address;
    FolderId folderId = new FolderId(WellKnownFolderName.Calendar, mailboxAddress);
    appt.Save(folderId);
    PropertySet properties = new PropertySet(AppointmentSchema.ICalUid);
    appt.Load(properties);
    CalendarView view = new CalendarView(DateTime.Today, DateTime.Today.AddDays(8)){PropertySet = properties};
    IEnumerable<Appointment> occurrences = service.FindAppointments(folderId, view)
        .Where(a => a.ICalUid == appt.ICalUid);
    ExtendedPropertyDefinition definition = new ExtendedPropertyDefinition(DefaultExtendedPropertySet.PublicStrings, "TestProperty", MapiPropertyType.String);
    Appointment firstOccurrence = occurrences.First();
    firstOccurrence.SetExtendedProperty(definition, "test");
    firstOccurrence.Update(ConflictResolutionMode.AutoResolve);
    //The error occurs on the next line.
    firstOccurrence.RemoveExtendedProperty(definition);
    firstOccurrence.Update(ConflictResolutionMode.AutoResolve);
    //clean up
    appt.Delete(DeleteMode.HardDelete);
}

似乎该错误仅针对Exchange 2007服务器（适用于2010）引发。是我做错了什么，还是 Exchange 有问题？ 有没有办法解决这个问题？ 任何帮助将不胜感激。

Answer 1

我最终没有使用RemoveExtendedProperty函数。 相反，我通过再次设置属性来解决此问题，但将其设置为空白区域。 然后，我在代码中处理了空白区域。 这似乎是 Exchange 或托管 API 的问题。

Answer 2

你试过吗？

appointment.Delete(DeleteMode.SoftDelete,SendCancellationsMode.SendToAllAndSaveCopy);